Football School: Inside Zone or Duo? Understanding the running game

Football School: Inside Zone or Duo? Understanding the running game


Message boards are full of so-called experts who never played or coached the game at the high levels. I’m one of them. CanesInSight is blessed to have Mike Zuckerman, a ten-year college coaching veteran, take us to Football School. He will join the show regularly to provide insight on terms we use every day, but may not fully understand. Zuck, a Miami alum, spent seven years in UM’s football program in various roles and, for the past three years, served as the linebackers coach at Utah State. During his tenure, Utah State had an 11-win season, won the conference, and produced 2023 first-team All-Conference LB MJ Tafisi. Zuck has taken a leave of absence to return to civilian life, which is a blow for Utah State but a blessing for Canes fans.

In this week’s Football School, he helps explain the inside running game and why fans are too quick to say their favorite team “always runs the same play up the middle”:

On zone versus gap scheme: This is the most basic way to think about it: in a zone scheme, every offensive lineman is going to step to the right (or left) and be responsible for their gap to the right (or left), and the run is going that direction. Whereas in a gap scheme, most of the time you're blocking down a gap and the running back is running opposite the flow of the line. In most cases, a gap scheme involves some type of pull, whether it be counter or power. Those are your traditional gap-scheme runs.

Zone is just everybody zoning an area. Then you get into your combination blocks within that, and it can get a lot more technical. But those are the most basic ways to look at zone versus gap scheme. We're going to talk later about Duo, and we'll go a lot more in depth. Duo is interesting because it’s technically a gap-scheme run. But it’s somewhere in between a gap and a zone scheme run because you're just responsible for an area in Duo, and there are no pullers. So it kind of blurs the lines between a zone and a gap run. We’ll get a lot more into that as we keep going.

On the classic zone-scheme team: There are very distinct differences between inside and outside zone. But if you think of Appalachian State and Louisville when Scott Satterfield was head coach, they were outside zone and inside zone all day. Miami itself, from the Al Golden era through Coach Diaz, was mostly an inside zone-based scheme. They were inside zone and there's a lot of different ways you can run inside zone.

In reality, for the majority of college football, their base run is inside zone. So if you turn on a game, and the commentators say “a draw play up the middle,” it’s often just inside zone out of shotgun. In college football, inside zone is the clear #1 run that you will actually see.

On the classic gap-scheme team: If you’re thinking power, Wisconsin is the first team that pops into my head. They're a little different now with Phil Longo going there. They're more spread out. Gus Malzahn loves power and counters. Anytime you see an offense that pulls a lot of people, that's a gap scheme. This year, Michigan ran a lot of gap schemes. It’s more downhill and in your face.

You see more RPO off the zone blocks. There are some off gap scheme, but when you're going to RPO off a gap scheme, you've got guys pulling and back blocks. That can be a lot harder to prevent the guy from hitting the quarterback when you're throwing an RPO.

On the required personnel for these different schemes: If you're going to be a zone team, the first question is, “Are you primarily inside zone or primarily outside zone?” Because I think outside zone is one of the hardest plays to coach and takes the most investment. So if you're going to be a primarily outside zone team, that's where you're recruiting more of the longer, more athletic guys.

I had a chance to play Oregon State at Utah State in 2021 in our bowl game. I thought their offensive line was very well coached and they were not that big. They were longer and taller than us, but they weren’t trying to blow people off the ball. They were super athletic because they ran a lot of outside zone. They could run and collect people and block guys in space.

When you're going to be a power, gap-scheme team, you're recruiting guys who can down block and drive people off the ball. So it allows you to recruit heavier guys. In college football today, there's still a level of athleticism needed because you're going to have to block some really good pass rushers off the edge. So it's not like you can just take people with no athleticism. But the more you're going to down block, the more you want bigger, stronger guys. You’ll be willing to sacrifice some of that ability to run in order to drive guys off the ball.


On inside zone: I always like starting with I-Backs when I explain these concepts. I did the same thing when I trained my linebackers, even though we might see two snaps of I-Backs the entire season. If you understand an I-Back run game, you understand every run game, because this is how gap structures are created.

Looking at this diagram we have up. This is a true I-formation. For the defense, I drew what's called an under front. Everything I draw today is going to be an under front. This simply means you've got this Sam (strongside backer) on the ball over here and a one and a five technique on the same side. Five technique means the defensive end lines up in the outside shade of the tackle. One technique is the nose is shaded on the outside shoulder of the center, towards the tight end side. That's all under means.

An inside zone scheme means these linemen up here are going to zone to the right. Let's say this is inside zone right. The back is going to roll to this side and either read the five technique or nose guard on the front side to cut back over here, just based on how those defensive guys are playing. The offensive line understands who they're blocking based off the front side. People are going to coach this different ways. Some people will say this RG should work from this five technique DE to the Mike (MLB). Some people will say he should slam back here on the nose and go to the Mike. But either way he's technically responsible for this zone.

If you're running a true zone scheme out of I-Backs, this fullback has to go back and cut off the remaining guy. That means the only unblocked guy, if people are playing a quarter scheme and the safety is a run-fitter, is this safety. The receiver is going to go and block him. So you're trying to read that front side. The line is moving the same direction as the running back.

The line right here is all stepping to the right. and the running back is going to the right. That's a major point of why that makes that inside zone.

If someone wants to get in a two-tight end formation, you just put the second tight end right here (replacing the fullback). Now they're in two tight ends running inside zone. It's the same play.

If we want to be in 11-personnel formation (one RB, one TE) and run zone-read, fine. Put this F out here [as a slot receiver]. It's all the same exact blocks. It's just, where is that fullback aligning? Is he a receiver now? Is he going across the ball? But essentially, this is inside zone. So you've got your line and running back going the same direction, and the running back pressing frontside to read it backside.

On the impact of a player like Elija Lofton: It's really hard to defend I-Backs. I'll give you an example from Utah State. The teams we played were extremely spread out. You saw all 11 personnel and 10 (1 RB, no TE) personnel pictures. Then all of a sudden, we go and play Wyoming. You can go look at the stats. It didn't go too well for us (Wyoming rushed for 330 yards). But in a week, you're trying to fit all these two-back run plays. It’s hard because it's not stuff you really see.

There are a lot of little tweaks you can do. You can really spot that fullback anywhere. Where Michigan made a lot of money is different fullback insertions. They can rep a lot of this and it's probably all just tags. And that tells them, “Okay, tackle, now you have to go block the defensive end because the fullback has to go block the Will.” So in one week to get ready for that when all you see is spread offense is really hard. Especially when people are motioning from out wide across the ball. That becomes really tricky because it's a lot of eye candy for your linebacker.

If you've got a fullback who can stay out there and run routes, that becomes really hard. You can't say he's always coming back in to block. You can line him up in the backfield and motion him out. Anytime you're motioning, you're forcing the defense to talk and communicate something in the structure of the defense. It could be a check, a guy having to bump out, or the safeties having to adjust. Motion makes defenses communicate and adjust. So I think the little tweaks that make offense simple make it hard on a defense and definitely made it hard on me. The more you can insert guys, the harder the run game is.


On power: So we’ve talked about zone. Now let’s understand gap scheme and power, and I'll show you how this leads to Duo. This is a traditional power play out of I-Backs. There’s a couple of different ways you can block it, but versus this front the fullback in power is always gonna block the Sam.

The backside guard is gonna pull for Mike and then you're gonna have a double team somewhere that's gonna go back to the Will. The center has to block back now because of this guard pulling and this tackle is gonna secure that and then hinge back for the defensive end. You can see the blue line is for the puller right there. That is your traditional power play.

The back is hitting it frontside and reading A to B to C to D to bounce.


On Duo: Someone described Duo to me as “power without a puller.” The fullback is going to kick out Sam, just like power. The back is gonna have the same read: A to B to C to D inside to roll it off the bounce. Now you double team with this tight end and tackle. We've eliminated that guard pull. So now they have more of a vertical double team based on where that Mike is aligned. They can truly fire off straight ahead because they should have a better angle to that Mike and can get more of a powerful down double team on the end. Now you have two double teams: “Duo.” That's how I learned it. You have a second double team here to get back to that Will who was accounted for by the front side double team in power. Then these two guys on the backside become true man blockers. They have to handle this tackle right here and this end right here.

Nowadays, a fullback just running and blocking a Sam on the line of scrimmage is not always a win for the offense, especially as fullbacks have become a dying breed. So how have people taken this Duo scheme to new formations?


In this picture right here, what they've done is taken the fullback and just made him a wing. This is a very common way people started running Duo. There's just not a lot of guys in football nowadays that can stand there and run and smash this Sam. This is a tough block that a lot of times is going to be a stalemate and not what you want to allow this guy to bounce this ball cleanly. So when this block is at the line of scrimmage, you can use a tight end-type who is less explosive as the “F.” It’s a much easier block. If he needs to, he can just wash him down. And it keeps the rest of this blocking scheme. You can see these guys are doing the exact same thing they were doing out of I-Backs.

Now, if you just leave this receiver out here and people are fitting with their safety, that's going to be a really hard block from this Z-WR to run all the way over there and block him to allow the running back to bounce it.

So what people do is they pre-snap motion the Z down or just align him in there with a cut split to allow him to block right there. And what that's going to do is make now our free hitter the corner. If the running back bounces the ball out, it should be a one-on-one between him and the corner. You should bet on your running back to win that play. More often than not, the corners aren't there to tackle running backs in the C or D gap.

The difference between inside zone and Duo: On inside zone, we talked about how these guys are all working the same direction of the running back. In Duo, or “power without a puller,” they're all down blocking the opposite direction of the flow of the running back. If it's all under center, it's really easy to see. But people start going shotgun and you can mess with the footwork out there. That’s where you get the murkiness between inside zone and Duo. It becomes really just the technique and who they're comboing to. That’s really how you're going to tell the difference.

On what happens when you replace the FB/second TE with a slot WR: Miami plays around with Duo by blocking with a receiver. This isn't just a Miami thing. You can get a really good running surface by using a wide receiver. If you're playing with a tight end, the Sam is going to line up on a tight end and the collision is going to happen right away. If you put a wide receiver there, and the defense uses a nickel, the nickel’s most likely going to be off the ball a little.

So now what you've done is create a soft edge here (with no defender lined up on the line) so the defense either has to put this DE in a nine technique (outside the tight end), in which case now you can double team him.

One thing I like in the Canes run game a lot is they sometimes bring those receivers in. You don't account for receivers being blockers in the run game. It's not something that you expect. I was at the Pinstripe Bowl this year. Rutgers did a really good job of using that receiver as a blocker and motioning him across. That’s becoming more common in college football.

On the trend of WRs becoming blockers: When you're introducing receivers, you're introducing weird people into the run fit that aren't used to fitting the run. So it's just creating extra surfaces and gaps. The reason it's become a big thing in the NFL is it's impossible in that league to line up in a basic formation and just run a run play. They're going to fit it well. They do football all day long. That's what they do.

So everything you do in the NFL is to try and create an extra gap and create matchups and different good angles for your guys to block, because you're playing against unbelievable defensive personnel every single week. In college, that stuff's hard. You better invest a lot in it and have special receivers, because the majority of college receivers aren't good blockers. When you see a good blocking wide receiver, he stands out.

It's mostly a ”want-to” thing as opposed to a physical thing. A lot of times, Miami uses Restrepo on those blocks. I don't know X that well, but I was there a little bit with him and I know he's super tough and super competitive. That goes a long way in blocking. I'd rather have a smaller guy that's going to give everything he's got than a physical dude who doesn't want to do it.

The Rams started this whole trend in college football, and really football in general, of all these complicated Duo schemes. Kentucky actually came and started doing it in college football, and you saw it more and more over the last few years. That’s why you see receivers blocking, because it's making it difficult on the defense to fit the run.


On running Duo out of bunch formations: This is probably the number one way you see Duo run now in college football. From a passing game standpoint, if you’re aligned in a bunch and the defense plays a two-high structure, you probably get both the corner and the safety off a little bit. So you've already put them where they're not in a great position to fit the run and can't tighten down.

With bunch, you get this easy block on the outside right there. The Z comes underneath for this safety. The corner is now right at the point of attack and having to make that play in the hole. That's a very common way people are blocking Duo nowadays out of a bunch. I see the Canes have done that a lot as well.


On his favorite Duo play from Miami’s film: This is something I saw the Canes do this year that I thought was good stuff. They’ve got 11 personnel. Three receivers over here on your right and they had this nub set in the boundary. What Miami started doing is they brought this guy in motion, still snap the ball when he's over here and brought him to block this guy. Why is this still Duo? Imagine you started [Restrepo] in I-Backs and told him to block that first guy outside, which is Sam. I know he's the corner in this picture, but for run game purposes, that guy is Sam. You can see how it's the same play.

So you started a guy as a receiver split out, thinking whoever's relating to this guy has nothing to do with the run game. Now you brought him into the run game and then, post snap, brought him across the ball, which means that you need to get somebody over there because you have a blocker for him. Now there is an extra gap in here created by a receiver. This isn't something common.

So now what’s the defense going to do to adjust to it? Are they going to bump the safeties and bring him down? Are they going to put the Sam down and bump the linebackers over? There’s movement. Your cleats aren't set. You have an extra gap over there, and it's from a receiver. So if you have a receiver who can block, it creates weird running scenarios that aren't your typical run game. I just thought that was something they did that was creative. What I see is every week, Miami tries to come up with some different way to run Duo and create surfaces. It’s all about creating good blocking surfaces.

Comments (5)

I’ve been waiting for this post since I heard the original podcast. No more excuses for calling every handoff out of the shotgun a “draw”, CIS!
Oklahoma had a GT counter blocked up the same exact **** way all the time, and then, they created RPOs out of it that could be a swing screen, a short dumpoff with the I-Back or H-Back leaking through the formation, etc.

I can see Lofton being exactly that.